Machine for making cross-bottom paper bags



1939- Y B. A. E. JOHN-SON 2,159,853

MACHINE FOR MAKING CROSS-BOTTOM PAPER BAGS Filed March 11, 1958 2 Sheets-Sheet l y 23, 1939- B. A, E. JOHNSON 2,159,853

MACHINE FOR MAKING CROSS-BOTTOM PAPER BAGS Filed March 11, 1938 h 2 Sheets-Sheet 2 ELL 7 Patented May 23, 1939 UNiTED s'rsr TENT OFFICE MACHINE FOR MG CROSS-BOTTOM PAPER BAGS stock company Application March 11,

1938, Serial N0. 195,368

In Sweden March 18, 1937 Claims.

This invention relates to an improved method and machine for making bags from paper or similar material and more particularly for the purpose of forming such bags with a cross-folded 5 bottom to obtain canister or satchel bags.

It is a main object of my invention to provide a simple method and means for facilitating the cross-folding of the bag bottom, without subjecting the bag blank to injurious stresses and for obtaining a very regular cross-bottom, particularly at its corners.

In the drawings:

Fig. 1 is a diagrammatic side view of a machine embodying my invention;

Fig. 2 is a side view on an enlarged scale of the essential parts of the machine;

Figs. 3 to 5 are perspective views illustrating successive steps of the operation of the cross-folding means of the machine;

Fig. 6 illustrates a bag with its cross-folded bottom, and

Fig. '7 illustrates the finished bag obtained after the closing of its cross-folded bottom.

As shown in Fig. l of the drawings, collapsed tubular bag blanks A are fed endwise upon an endless belt I towards a bottom folding drum l3.

The tubular blanks are out and formed with semicircular fiaps B when they pass between rollers 40 and 4| onto an endless belt 42, which travels around a driving pulley 29 and a supporting pulley 56. The belt I has drivers 28 engaging the rear ends of the bag blanks A, so as to advance the latter. Above the belt I is arranged a drum 2 and a guide plate 3 which extends along the periphery of said drum in slightly spaced relation thereto, so that the bag blanks are introduced between the drum and the guide plate. The drum 2 is rotatably mounted on a fixed shaft 5 and driven in the direction of the arrow (Fig. 2) by a gear wheel I which meshes with another gear wheel 8 which forms a part of the drum 2. The gear wheel I is secured to the pulley 29-. A cam I2 is fixed to the non-rotatable shaft 6 and a roller 9 is adapted to ride on said cam. The roller 9 is mounted on a lever arm II. A tension spring It is attached to the arm I! and to the drum 2 to force the roller 9 against the cam I2. A finger 4 forms a part of the lever I! and projects normally slightly beyond the periphery of the drum 2 and is adapted to coact with an abutment 5 on the drum. Two diametrically oppositely disposed gripper mechanisms of this kind are provided in the drum 2. Parallel with. the shaft 6 extends another non-rotatable shaft I5 on which is rotatably mounted the bottom-folding drum [3. The

drum I3 has a toothed ring I6 which meshes with the gear wheel 8 of the drum 2, so that the driving drum 2 and the driven drum l3 are arranged to rotate in opposite directions.

The drum I3 has in its periphery axially extending recesses 0r grooves l1 adapted to receive ribs I8 which are attached transversely to two parallel endless steel belts IS. The belts I9 pass beneath and around the ends of the drum 2 and from there upwardly around the ends of the bottom-folding drum I3, whereafter they pass around guide pulleys 20 back to the drum 2. A hook I4 is pivotally journalled on a pin 3| in the drum i3 and secured to an arm 32 to which is pivoted a link rod 33. To the shaft [5 is secured a cam disc 34 upon which rides a roller 36 which is journalled on an arm 35. To the arm 35 and to the drum I3 is attached a tension spring 43 adapted to force the roller 35 against the cam disc 34. The arm 35 is pivotally journalled on a shaft 3? in the drum I3 and rigidly connected to another arm 38 which is pivotally connected to the link rod 33. The cam disc 34 has such a shape that the hook I4 is maintained in an outwardly turned position until it has passed the drum 2, whereafter the cam 34 allows the hook to be swung inwardly and rearwardly to catch an edge of the bag supplied endwise to the drum l3.

Above the drum 2 and parallel therewith extends a fixed shaft 2!. To the shaft 2| is adjustably secured a bracket 22 which has a plate 23 at a right angle to the drums 2 and I3. Said plate has a lower and front edge or face which conforms to the peripheries of the drums 2 and I3 and are slightly spaced apart therefrom as shown in Fig. 2. As each side of the plate 23 are positioned laterally directed or diverging nozzles 24 which are directed substantially towards the narrow space between the drums 2 and I3. The nozzles are connected to a header 24 which is connected to an air compressor 39 by means of a conduit 26 which has a central valve 40. The valve 4B is by means of an arm 44 connected to a link rod 45 which, in turn, is pivotally connected to a double lever 46 which is pivotally mounted on a shaft 41. The lever 46 has a roller 55 which rides on a cam @3- which is attached to the driving shaft is to which the belt pulley 29 is secured. Two upwardly converging slightly curved ironing bars 21 are by means of pins 5| adjustably attached to the bracket 22. The bars 21 are curved into conformity with the periphery of the drum l3 and spaced apart slightly therefrom.

In operation, the flat tubular blank A is introduced by the belt I between the guide plate 3 and the continuously revolving drum 2, so that the flap B enters beneath an abutment 5 on the drum 2. Then the cam l2 forces the finger 5 inwardly and rearwardly, so that the flap B is clamped between the finger 4 and the abutment 5, whereafter the bag blank is pulled by its flap B endwise up between the drums 2 and I3. Thereby, a clamping rib !8 follows the movement of the bag and when the steel bands 99 are about to shift their movement to the drum I3 the clamping rib l8 enters a groove ll on the drum l3. At that moment the different parts of the machine are about to assume the positions shown in Fig. 2 and the flap B of the bag blank has been bent slightly outwardly from the drum is. By suitable relative adjustments and arrangements of the positions oi the ribs l8 on the bands E9, of the tongs 4, 5 in the drum 2, of the grooves 51 in the drum is, and of the drivers 28 on the belt I as well as the relative positions of the drums 2 and 13 the clamping ribs !8 will clamp the bag blanks to the drum I 3 at exactly the desired distance from their foremost ends. Now the cam disc 35 allows the hook Hi to swing rearwardly and inwardly to catch the inner edge of the foremost end of the bag blank, whereby the upwardly projecting end portion of the clamped bag blank is opened slightly, as shown in Figs. 2 and 3, when the drums'Z and I3 have continued their rotary motion somewhat. Now the cam 48 opens the control valve 40, so that a jet of air is projected from each nozzle 24 into the partly opened bag blank end. The jets of air are directed substantially towards the corners D formed at the bottom of the portion of the bag blank that projects above the clamping rib. Thereby, said corners are expanded, so that they will be folded into a very regular shape with distinct folds at the subsequent cross-folding of said end portion. When the different parts or the mechanisms have assumed the positions shown in Fig. 4 the tongs 6, 5 release the flap 'B, whereat the plate 23 has entered the bag blank end. On continued movement of the drum l3 the bag blank clamped between the rib !8 and the drum I3 is moved upwardly past the cross-folding plate 23 and thereby the outer side of the end portion of the bag blank is folded outwardly and rearwardly about the rib 98, as shown in'FigJE, so that it is bent down upon the outer face of the bag blank, whereby the edges C of the bag blank are bent towards one another. The ironing bars 2'! complete this cross-folding and the bag blank end obtains the shape illustrated in Fig. 6. Thereafter the flaps E and F of the cross-folded bottom are bent outwardly from the drum' l3, and the closing and sealing of the bottom of the bag is completed by any suitable means such as those described and illustrated in the Patent No. 1,894,726 to Beckman.

I claim:

1. In a machine for making cross-bottom paper bags; a continuously movable conveyonmeans to feed collapsed tubular bag blanks endwise, said blanks having been placed longitudinally on said conveyor, a clamping'member having a straight edge, means to move said clamping member so as to place said straight edge across a bag blank and press same against said conveyor and move transversely together with said conveyor, a folding member operative in slightly spaced relation to said conveyor to enter said blank end when the blankis advanced by said conveyor and fold one wall of said end rearwardly about said straight edge upon said clamping member when said clamping member is moved transversely past said folding member, and a nozzle positioned on each side of said folding member to project a jet of air into the corners of the bag blank end defined by said straight edge of said clamping memher.

2. In a machine for making cross-bottom paper bags, a continuously movable conveyor, means to feed collapsed tubular bag blanks endwise, said blanks having been placed longitudinally on said conveyor, a clamping member having a straight edge, means to move said clamping member so as to place said straight edge across a bag blank and press same against said conveyor and move transversely together with said conveyor, a stationary folding member positioned in slightly spaced relation to said conveyor to enter said blank end when the blank is advanced by said conveyor and fold one Wall of said end rearwardly about said straight edge upon said clamping member when said clamping member is moved transversely past said folding member, and a nozzle positioned on each side of said folding member to project a jet of air into the corners of the bag blank end defined by said straight edge of said clamping member.

3. In a machine for making cross-bottom paper bags, a continuously movable conveyor, means to feed collapsed tubular bag blanks endwise, said blanks having been placed longitudinally on said conveyor, a clamping member having a straight edge, means to move said clamping member so as to place said straight edge across a bag blank and press same against said conveyor and move transversely together with said conveyor, a folding member operative in slightly spaced relation to said conveyor to enter said blank end when the blank is advanced by said conveyor and fold one wall of said end rearwardly about said straight edge upon said clamping member when said clamping member is moved transversely past said folding member, and a nozzle positioned on each side of said folding member, said nozzles diverging so as to project a jet of air into both the v corners of the blank end defined by said straight edge of said clamping member.

4. In a machine for making cross-bottom paper bags, a continuously movable conveyor, meansto feed collapsed tubular bag blanks endwise, said blanks'having been placed longitudinally on said conveyor, a clamping member having a straight edge, means to move said clamping member so as to place said straight edge across a bag blank and press same against said conveyor and move transversely together with said conveyor, a stationary plate positioned edgewise in the direction of travel of said conveyor in slightly spaced relation to said conveyor to enter said blank end when the blank is advanced by said conveyor and fold one wall of said end rearwardly about said straight edge upon said clamping member when said clamping member is moved transversely past said folding member, and a nozzle positioned on each side of said plate to project a jet of air into the corners of the bag blank end defined by said straight edge of said clamping member.

5. In a machine for making cross-bottom paper bags, a continuously movable conveyor, means to feed collapsed tubular bag blanks endwise, said blanks having been placed longitudinally on said conveyor, a clamping member having a straight edge across a bag blank and press same against said conveyor and move transversely together with said conveyor, mechanical means for openclamping member when said clamping member is ing an end of the clamped bag blank projecting beyond said edge, a folding member operative in sequence to said mechanical means and in slightly spaced relation to said conveyor to enter said iank end when the blank is advanced by said conveyor and fold one Wall of said blank end rearwardly about said straight edge upon said.

moved transversely past said folding member, and a nozzle positioned on each side of said folding member to project a jet of air into the corners of the bag blank end defined by said straight edge of said clamping member.

BROR ANDERS EMIL JOHNSON. 

